Modern aircraft have braking systems including electric brakes provided with electromechanical actuators.
Each actuator comprises a pusher facing a stack of disks and moved under drive from an electric motor to apply a braking force on the stack of disks in selective manner.
Such brakes are generally under force control based on a braking setpoint.
The invention applies more particularly to an actuator provided with a sensor for sensing pusher position, but not including a force sensor capable of measuring the force applied by the pusher against the stack of disks.
Under such circumstances, in order to be able to servo-control the force applied by such actuators, it is necessary to estimate the force being applied by a pusher as a function of parameters that can be measured, such as the position of the pusher, or indeed the power supply current being drawn by the electric motor.
Alternatively, the braking setpoint can be converted into a position setpoint, whereupon position servo-control can be performed.
The servo-control that is implemented generally depends on parameters, relationships, and models that are estimated a priori. However, the conditions under which a brake operates can change during the lifetime of the brake, thus making servo-control thereof less accurate.
It is known, in particular from U.S. Pat. No. 6,178,369, to adjust a relationship between the braking setpoint and the position setpoint in order to take account of the operating conditions of the brake, and in particular its temperature or the degree of wear of its disks. To this end, the brake is caused to operate under conditions in which the force applied by the pusher on the friction elements depends essentially on a current fed to the electric motor, and for one or more operating points, the position of the pusher and the force it exerts are observed. These position-and-force pairs as measured in this way are used to adjust the relationship, e.g. by a conventional regression method.